Question: Have you played Grimm before? I haven't. Saturday will be the first. We'll make dinner - gamers, like a movie crew, work better together when you feed them - make characters, and play one or two scenes, primarily to test out the mechanics of the game. I'll be running a simple, "Fair is Foul, Foul is Fair" themed game, which they should figure out by story's end. A half dozen scenes, perhaps, to get to a conclusion.
Reading Chapter 6, Running the Game, last night, I found it lacking. While there is plenty of advice, it boils down to "find a Grimm story, change something, make it an unhappy ending." I'd rather the authors did that, took "Little Red Riding Hood" and whipped up a simple Grimm Lands version, than offer what seems common sense advice. That said, I'm very familiar with rpgs and with creating rpg sessions, and this chapter might have been written with the neophyte in mind.